1. Field of the Invention
This invention relates generally to endoscopic procedures and medical devices useful in such procedures and more particularly to an endoscopic procedure wherein a small caliber fiber optic bundle is used to remotely view the operative end of a catheter.
2. Brief Description of the Background
When performing endoscopic procedures, it is necessary to place the operative end of the endoscope in proper relation to the target body tissue so that the desired medical procedure may be performed. It is necessary, therefore, that some means be available by which to observe such operative part, thus enabling guidance to the part of the body Where medical intervention is required.
Commonly, endoscopes have fiber optic bundles disposed through one channel of the endoscope. A portion of the fibers transmit light to the internal body cavity. The clinician views internally by way of return (or image forming) light which passes through some amplification device, often an adapted magnifying lens. In this manner, the clinician may directly view the collected image.
This arrangement of a fiber optic bundle within an endoscope has several disadvantages. The ability to position the endoscope is impaired since the field of vision is limited to internal features in the path of the endoscope's distal end. A primary drawback is, then, that the operative end of the endoscope may not be visible because it is behind or beside the field of vision from the fiber optic bundle. When more than one operative medical device is disposed within a multi-lumen endoscope, placement of any one of such devices may be further complicated. For example, if one lumen of the endoscope contains a grasping forcep while another contains a loop retrieval wire, the physician may expend a great deal of effort as he determines the exact position of the desired operative device needed to perform the medical procedure. There is also a potential that the two devices may become entangled.
The relatively extended position of the operative end is nearly impossible to determine in the commonly used endoscope. Even if the operative end is visible, the depth relationship between it and other instruments or the body tissues is indeterminate since the field of vision is parallel with the operative end. The image observed by the physician cannot accurately relay depth information since such linear observations are inherently two-dimensional. In other words, this operative end may be in various positions of relative extension or retraction, which positions may remain undetectable through the common endoscope until actual contact with the body tissue is achieved. Thus when placing the endoscope for effective treatment or diagnosis, the clinician must use some guesswork to avoid damaging tissue or missing the target.
Another disadvantage of endoscopic procedures wherein the endoscope contains the fiber optic bundle is that the diameter of the endoscope must be large enough to accommodate the fiber optic bundle. This creates impediments to effective medical procedure. First, the trauma experienced with advancing an endoscope, either through existing anatomical ducts or percutaneously, increases with increased endoscope size. Also, larger endoscopes are less deflectable.
Another common medical procedure employs a catheter without a fiber optic bundle disposed within one of its lumens. The catheter is advanced into the body cavity toward the target tissue under external guidance. For example, the endoscope may be advanced to the ultimate location using x-ray (fluoroscopic) or ultrasound guidance. This method of indirectly positioning a catheter has disadvantages. Great interpretive skill may be required to correctly position and manipulate the operative tip, since the returned visual imagery is an indirect representation of the actual internal cavity.
The endoscopic procedure of the present invention overcomes these disadvantages in present medical procedures. It allows real image visualization of the operative tip of an advancing catheter as that advancement relates to the target tissue. Since the fiber optic bundle is removed from the catheter, the catheter's diameter may he decreased or alternatively, its functionality may be increased. Should the diameter be decreased, the catheter becomes actively deflectable. Moreover, the present procedure is atraumatic as compared to percutaneous access in certain endoscopic procedures presently in use where the endoscopic access is through punctures.
Various medical devices using fiber optics have been developed, none of which disclose the principles of the present invention.
Northeved U.S. Pat. No. 3,961,621, discloses a device comprised of an elongated bevel cut needle with a tubular stiletto disposed therein capable of taking biological samples from a human body. Fiber optic bundles are disposed in parallel with and circumferentially of the stiletto for use in guiding the stiletto to the target tissue. A vacuum may be applied through fine air ducts alternately disposed with the fiber optic bundles.
Matsuo, U.S. Pat. No. 4,269,192, discloses a medical instrument comprising a tubular member which has a bevel cut end. The intensity of light emitted into the body and then reflected from the examination area activates an LED which signals the intensity of the reflected light indicating the location of the operative end of the instrument. The fiber optics are disposed axially within the operative tubular member.
Takahashi, U.S. Pat. No. 3,556,085, discloses a microscope adapted for insertion into the human body comprising a bevel cut fiber optic system and incorporating magnifying objective lenses and an eye piece. The lens system is variously positionable to achieve different levels of magnification. The microscope is designed for use with with an operative medical instrument disposed in parallel with the fiber optics and in the same housing.
Olinger, U.S. Pat. No. 3,941,121, discloses a small caliber endoscope including a hollow needle with a lens system and image transmitting fiber optic bundle within the needle. A channel for receiving an operative medical instrument, specifically an electrode for stimulating spinal nerves, is provided. The operative channel is disposed longitudinally parallel with the fiber optic bundle.
Kapany,. U.S. Pat. No. 3,349,762, discloses a medical instrument for measuring blood flow velocity using fiber optics to determine the intensity of the light transmitted by flowing blood. The intensity is measured by a photocell and converted to an analog voltage or current output.
Liese, U.S. Pat. No. 4,566,438, discloses a stylet incorporating fiber optic bundles to return the intensity and color of reflected light in order to localize a needle tip. The fiber optics are beveled at one end and the encasement is closed with a low vapor pressure epoxy. The receiving fiber has a reflective surface adjacent to the beveled end of the instrument.
None of these patents disclose a medical procedure wherein a very small fiber optic bundle is inserted through the lumen of a prepositioned needle in order to remotely direct the operative tip of another medical instrument via direct visualization of instrument's operative tip.